Don't use the abbrevation "Sep." in UI text

(cherry picked from commit 5046a7d1b1cf22634b0011fc71b7c82a7e3d2bd3)

editor/plugins/texture_region_editor_plugin.cpp

@@ -1047,7 +1047,7 @@ TextureRegionEditor::TextureRegionEditor(EditorNode *p_editor) {
 	hb_grid->add_child(sb_step_y);
 
 	hb_grid->add_child(memnew(VSeparator));
-	hb_grid->add_child(memnew(Label(TTR("Sep.:"))));
+	hb_grid->add_child(memnew(Label(TTR("Separation:"))));
 
 	sb_sep_x = memnew(SpinBox);
 	sb_sep_x->set_min(0);

editor/plugins/theme_editor_plugin.cpp

@@ -702,7 +702,7 @@ ThemeEditor::ThemeEditor() {
 	test_menu_button->get_popup()->add_radio_check_item(TTR("Radio Item"));
 	test_menu_button->get_popup()->add_radio_check_item(TTR("Checked Radio Item"));
 	test_menu_button->get_popup()->set_item_checked(7, true);
-	test_menu_button->get_popup()->add_separator(TTR("Named Sep."));
+	test_menu_button->get_popup()->add_separator(TTR("Named Separator"));
 
 	PopupMenu *test_submenu = memnew(PopupMenu);
 	test_menu_button->get_popup()->add_child(test_submenu);